#!/usr/bin/node
const EventEmitter=require('events').EventEmitter;
function Dog(name,energy){
  let _name=name,
      _energy=energy,
      that=this;
  //调用基类的构造函数
  EventEmitter.call(this);

  let timer=setInterval(()=>{
    if(_energy>0){
      that.emit('bark');
      _energy--;
    }else{
      clearInterval(timer);
    }
  } ,1000);
  this.name=()=>_name;
  this.energy=()=>_energy;
}

//原型链
Dog.prototype=EventEmitter.prototype;

module.exports=Dog;
